Re: [PATCH v4 02/18] vfio: Move iova_bitmap into iommufd

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 18 Oct 2023 21:26:59 +0100
Joao Martins <joao.m.martins@oracle.com> wrote:

> Both VFIO and IOMMUFD will need iova bitmap for storing dirties and walking
> the user bitmaps, so move to the common dependency into IOMMUFD.  In doing
> so, create the symbol IOMMUFD_DRIVER which designates the builtin code that
> will be used by drivers when selected. Today this means MLX5_VFIO_PCI and
> PDS_VFIO_PCI. IOMMU drivers will do the same (in future patches) when
> supporting dirty tracking and select IOMMUFD_DRIVER accordingly.
> 
> Given that the symbol maybe be disabled, add header definitions in
> iova_bitmap.h for when IOMMUFD_DRIVER=n
> 
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  drivers/iommu/iommufd/Kconfig                 |  4 +++
>  drivers/iommu/iommufd/Makefile                |  1 +
>  drivers/{vfio => iommu/iommufd}/iova_bitmap.c |  0
>  drivers/vfio/Makefile                         |  3 +--
>  drivers/vfio/pci/mlx5/Kconfig                 |  1 +
>  drivers/vfio/pci/pds/Kconfig                  |  1 +
>  include/linux/iova_bitmap.h                   | 26 +++++++++++++++++++
>  7 files changed, 34 insertions(+), 2 deletions(-)
>  rename drivers/{vfio => iommu/iommufd}/iova_bitmap.c (100%)


Reviewed-by: Alex Williamson <alex.williamson@redhat.com>


> 
> diff --git a/drivers/iommu/iommufd/Kconfig b/drivers/iommu/iommufd/Kconfig
> index 99d4b075df49..1fa543204e89 100644
> --- a/drivers/iommu/iommufd/Kconfig
> +++ b/drivers/iommu/iommufd/Kconfig
> @@ -11,6 +11,10 @@ config IOMMUFD
>  
>  	  If you don't know what to do here, say N.
>  
> +config IOMMUFD_DRIVER
> +	bool
> +	default n
> +
>  if IOMMUFD
>  config IOMMUFD_VFIO_CONTAINER
>  	bool "IOMMUFD provides the VFIO container /dev/vfio/vfio"
> diff --git a/drivers/iommu/iommufd/Makefile b/drivers/iommu/iommufd/Makefile
> index 8aeba81800c5..34b446146961 100644
> --- a/drivers/iommu/iommufd/Makefile
> +++ b/drivers/iommu/iommufd/Makefile
> @@ -11,3 +11,4 @@ iommufd-y := \
>  iommufd-$(CONFIG_IOMMUFD_TEST) += selftest.o
>  
>  obj-$(CONFIG_IOMMUFD) += iommufd.o
> +obj-$(CONFIG_IOMMUFD_DRIVER) += iova_bitmap.o
> diff --git a/drivers/vfio/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c
> similarity index 100%
> rename from drivers/vfio/iova_bitmap.c
> rename to drivers/iommu/iommufd/iova_bitmap.c
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index c82ea032d352..68c05705200f 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -1,8 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_VFIO) += vfio.o
>  
> -vfio-y += vfio_main.o \
> -	  iova_bitmap.o
> +vfio-y += vfio_main.o
>  vfio-$(CONFIG_VFIO_DEVICE_CDEV) += device_cdev.o
>  vfio-$(CONFIG_VFIO_GROUP) += group.o
>  vfio-$(CONFIG_IOMMUFD) += iommufd.o
> diff --git a/drivers/vfio/pci/mlx5/Kconfig b/drivers/vfio/pci/mlx5/Kconfig
> index 7088edc4fb28..c3ced56b7787 100644
> --- a/drivers/vfio/pci/mlx5/Kconfig
> +++ b/drivers/vfio/pci/mlx5/Kconfig
> @@ -3,6 +3,7 @@ config MLX5_VFIO_PCI
>  	tristate "VFIO support for MLX5 PCI devices"
>  	depends on MLX5_CORE
>  	select VFIO_PCI_CORE
> +	select IOMMUFD_DRIVER
>  	help
>  	  This provides migration support for MLX5 devices using the VFIO
>  	  framework.
> diff --git a/drivers/vfio/pci/pds/Kconfig b/drivers/vfio/pci/pds/Kconfig
> index 407b3fd32733..fff368a8183b 100644
> --- a/drivers/vfio/pci/pds/Kconfig
> +++ b/drivers/vfio/pci/pds/Kconfig
> @@ -5,6 +5,7 @@ config PDS_VFIO_PCI
>  	tristate "VFIO support for PDS PCI devices"
>  	depends on PDS_CORE
>  	select VFIO_PCI_CORE
> +	select IOMMUFD_DRIVER
>  	help
>  	  This provides generic PCI support for PDS devices using the VFIO
>  	  framework.
> diff --git a/include/linux/iova_bitmap.h b/include/linux/iova_bitmap.h
> index c006cf0a25f3..1c338f5e5b7a 100644
> --- a/include/linux/iova_bitmap.h
> +++ b/include/linux/iova_bitmap.h
> @@ -7,6 +7,7 @@
>  #define _IOVA_BITMAP_H_
>  
>  #include <linux/types.h>
> +#include <linux/errno.h>
>  
>  struct iova_bitmap;
>  
> @@ -14,6 +15,7 @@ typedef int (*iova_bitmap_fn_t)(struct iova_bitmap *bitmap,
>  				unsigned long iova, size_t length,
>  				void *opaque);
>  
> +#if IS_ENABLED(CONFIG_IOMMUFD_DRIVER)
>  struct iova_bitmap *iova_bitmap_alloc(unsigned long iova, size_t length,
>  				      unsigned long page_size,
>  				      u64 __user *data);
> @@ -22,5 +24,29 @@ int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,
>  			 iova_bitmap_fn_t fn);
>  void iova_bitmap_set(struct iova_bitmap *bitmap,
>  		     unsigned long iova, size_t length);
> +#else
> +static inline struct iova_bitmap *iova_bitmap_alloc(unsigned long iova,
> +						    size_t length,
> +						    unsigned long page_size,
> +						    u64 __user *data)
> +{
> +	return NULL;
> +}
> +
> +static inline void iova_bitmap_free(struct iova_bitmap *bitmap)
> +{
> +}
> +
> +static inline int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,
> +				       iova_bitmap_fn_t fn)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline void iova_bitmap_set(struct iova_bitmap *bitmap,
> +				   unsigned long iova, size_t length)
> +{
> +}
> +#endif
>  
>  #endif